SOLID-STATE IMAGING DEVICE, FABRICATION METHOD THEREOF, IMAGING APPARATUS, AND FABRICATION METHOD OF ANTI-REFLECTION STRUCTURE

• US 20100244169A1
• Filed: 03/22/2010
• Published: 09/30/2010
• Est. Priority Date: 03/31/2009
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sasaki, Tohru, Maeda, Kensaku, Koike, Kaoru, Tatsumi, Tetsuya
• Granted Patent: US 8,685,856 B2
• Time in Patent Office: Days
• US Class Current: 257/432
• CPC Class Codes: G02B 1/118 having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: H01L 21/0335 characterised by their behaviour during the process, e.g. soluble masks, redeposited masks
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: H01L 27/1462 Coatings
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A fabrication method of an anti-reflection structure includes the steps of: forming a resin film having micro-particles dispersed therein on a surface of a substrate; forming a protrusion dummy pattern on the resin film by etching the resin film using the micro-particles in the resin film as a mask while gradually etching the micro-particles; and forming a protrusion pattern on the surface of the substrate by etching back the surface of the substrate together with the resin film having the protrusion dummy pattern formed thereon, and transferring a surface shape of the protrusion dummy pattern formed on a surface of the resin film to the surface of the substrate.

Claims

1. A fabrication method of an anti-reflection structure, the method comprising the steps of:

forming a resin film having micro-particles dispersed therein on a surface of a substrate;

forming a protrusion dummy pattern on the resin film by etching the resin film using the micro-particles in the resin film as a mask while gradually etching the micro-particles; and

forming a protrusion pattern on the surface of the substrate by etching back the surface of the substrate together with the resin film having the protrusion dummy pattern formed thereon, and transferring a surface shape of the protrusion dummy pattern formed on a surface of the resin film to the surface of the substrate.

2. The fabrication method of an anti-reflection structure according to claim 1, wherein the resin film having the micro-particles dispersed therein is formed by a coating method.

3. The fabrication method of an anti-reflection structure according to claim 1 or 2, wherein

the micro-particles are made from metal oxides or a phthalocyanine compound;

and

the resin film is selected from the group consisting of a novolac-based resin, a styrene-based resin, an acrylic resin, a polysiloxane-based resin, and a polyimide-based resin.

4. The fabrication method of an anti-reflection structure according to claim 1 or 2, wherein the resin film contains a heat curing agent.

5. A fabrication method of an anti-reflection structure, the method comprising the steps of:

arranging micro-particles on a surface of a substrate; and

forming a protrusion pattern on the surface of the substrate by performing anisotropic etching in which an etching rate for the substrate is higher than an etching rate for the micro-particles.

6. The fabrication method of an anti-reflection structure according to claim 5, wherein the micro-particles are arranged on the surface of the substrate by forming a solvent having the micro-particles dispersed therein on the surface of the substrate in a film form.

7. The fabrication method of an anti-reflection structure according to claim 6, wherein the micro-particles are arranged on the surface of the substrate by coating the solvent having the micro-particles dispersed therein onto the surface of the substrate in a film form by a coating method and then evaporating the solvent.

8. The anti-reflection structure fabrication method of an anti-reflection structure according to claim 5, wherein a relationship of etching selectivity between the substrate and the micro-particles during the etching in the protrusion pattern forming step is varied so that the etching rate for the substrate is higher than the etching rate for the micro-particles.

9. The fabrication method of an anti-reflection structure according to claim 5, wherein the micro-particles are made from inorganic particles selected from oxides, nitrides, carbides, borides, sulfides, and metal, or organic particles.

10. A fabrication method of a solid-state imaging device, the method comprising the steps of:

forming an interlayer insulating film on a semiconductor substrate, in which a photoelectric conversion portion that converts an incident light to signal charges and a charge transfer portion that reads out and transfers the signal charges from the photoelectric conversion portion are formed, and forming a planarization insulating film thereon;

forming a resin film having micro-particles dispersed therein on the planarization insulating film;

forming a protrusion dummy pattern on the resin film by etching the resin film using the micro-particles in the resin film as a mask while gradually etching the micro-particles; and

forming a protrusion pattern on the surface of the planarization insulating film by etching back the surface of the planarization insulating film together with the resin film having the protrusion dummy pattern formed thereon, and transferring a surface shape of the protrusion dummy pattern formed on a surface of the resin film to the surface of the planarization insulating film.

11. A fabrication method of a solid-state imaging device, the method comprising the steps of:

forming an interlayer insulating film on a semiconductor substrate, in which a photoelectric conversion portion that converts an incident light to signal charges and a charge transfer portion that reads out and transfers the signal charges from the photoelectric conversion portion are formed, and forming a planarization insulating film thereon;

arranging micro-particles on a surface of the planarization insulating film; and

forming a protrusion pattern on the surface of the planarization insulating film by performing anisotropic etching in which an etching rate for the planarization insulating film is higher than an etching rate for the micro-particles.

12. A solid-state imaging device comprising:

a photoelectric conversion portion that is disposed in a semiconductor region so as to obtain signal charges by performing photoelectric conversion on an incident light; and

a plurality of layers of light transmissive films formed on the photoelectric conversion portion,

wherein an anti-reflection structure is formed on a surface of the semiconductor region or a surface of a first light transmissive film on at least one layer of the plurality of layers of the light transmissive films;

the anti-reflection structure is constructed from spindle-shaped protrusions which have light transmissive properties and a sinusoidal curved surface and are arranged on the surface of the first light transmissive film or the surface of the semiconductor region; and

the protrusions have a height which is equal to or greater than 50 nm and equal to or less than 100 nm for an arrangement pitch of 40 nm, equal to or greater than 200 nm and equal to or less than 400 nm for an arrangement pitch of 100 nm, and equal to or greater than 50 nm and equal to or less than 400 nm for an arrangement pitch of 200 nm.

13. The solid-state imaging device according to claim 12, wherein a height-wise volume variation of each protrusion decreases in a linear fashion from the bottom to the apex of each protrusion.

14. The solid-state imaging device according to claim 12, wherein the first light transmissive film is a microlens that condenses an incident light to the photoelectric conversion portion, a passivation film that is formed above the photoelectric conversion portion, an inorganic anti-reflection film that is formed on the photoelectric conversion portion, or a cover glass or infrared cut-off filter that is formed in an outermost portion of a region where the incident light is incident.

15. A fabrication method of a solid-state imaging device, the method comprising the step of:

forming an anti-reflection structure on a surface of a first light transmissive film on at least one layer of a plurality of layers of light transmissive films when the plurality of layers of the light transmissive films are formed on a photoelectric conversion portion that is disposed in a semiconductor region so as to obtain signal charges by performing photoelectric conversion on an incident light

wherein the anti-reflection structure forming step includes the steps of

forming a UV-curable film on the surface of the first light transmissive film,

transferring a shape of spindle-shaped protrusions having a sinusoidal curved surface to a surface of the UV-curable film by pressing a UV-transmitting nanoimprint mold, in which spindle-shaped depressions having a sinusoidal curved surface are arranged on an entire surface, against the UV-curable film,

curing the UV-curable film by irradiation with ultraviolet rays in a state where the nanoimprint mold is pressed,

separating the nanoimprint mold from the UV-curable film, and

transferring a shape of spindle-shaped protrusions having a sinusoidal curved surface formed on the UV-curable film to the surface of the first light transmissive film by etching back the UV-curable film and an upper portion of the first light transmissive film, and

the protrusions are formed to have a height which is equal to or greater than 50 nm and equal to or less than 100 nm for an arrangement pitch of 40 nm, equal to or greater than 200 nm and equal to or less than 400 nm for an arrangement pitch of 100 nm, and equal to or greater than 50 nm and equal to or less than 400 nm for an arrangement pitch of 200 nm.

16. The fabrication method of a solid-state imaging device according to claim 15, wherein a height-wise volume variation of each protrusion decreases in a linear fashion from the bottom to the apex of each protrusion.

17. A fabrication method of a solid-state imaging device, the method comprising the step of:

forming an anti-reflection structure on a surface of a first light transmissive film on at least one layer of a plurality of layers of light transmissive films when the plurality of layers of the light transmissive films are formed on a photoelectric conversion portion that is disposed in a semiconductor region so as to obtain signal charges by performing photoelectric conversion on an incident light,

wherein the anti-reflection structure forming step includes the steps of

forming the first light transmissive film from a UV-curable or heat-curable coating film,

transferring a shape of spindle-shaped protrusions having a sinusoidal curved surface to a surface of the first light transmissive film by pressing a UV-transmitting nanoimprint mold, in which spindle-shaped depressions having a sinusoidal curved surface are arranged on an entire surface, against the first light transmissive film,

curing the first light transmissive film by irradiation with ultraviolet rays in a state where the nanoimprint mold is pressed, and

separating the nanoimprint mold from the first light transmissive film, and

the protrusions are formed to have a height which is equal to or greater than 50 nm and equal to or less than 100 nm for an arrangement pitch of 40 nm, equal to or greater than 200 nm and equal to or less than 400 nm for an arrangement pitch of 100 nm, and equal to or greater than 50 nm and equal to or less than 400 nm for an arrangement pitch of 200 nm.

18. The fabrication method of a solid-state imaging device according to claim 17, wherein a height-wise volume variation of each protrusion decreases in a linear fashion from the bottom to the apex of each protrusion.

19. An imaging apparatus comprising:

a light-condensing optical unit that condenses an incident light;

an imaging unit having a solid-state imaging device which receives the light condensed by the light-condensing optical unit and performs photoelectric conversion on the light; and

a signal processing portion that processes signals having been subjected to the photoelectric conversion,

wherein the solid-state imaging device includes

a photoelectric conversion portion that is disposed in a semiconductor region so as to obtain signal charges by performing photoelectric conversion on an incident light, and

a plurality of layers of light transmissive films formed on the photoelectric conversion portion;

an anti-reflection structure is formed on a surface of the semiconductor region or a surface of a first light transmissive film on at least one layer of the plurality of layers of the light transmissive films;

the anti-reflection structure is constructed from spindle-shaped protrusions which have light transmissive properties and a sinusoidal curved surface and are arranged on the surface of the first light transmissive film or the surface of the semiconductor region; and

the spindle-shaped protrusions have a height which is equal to or greater than 50 nm and equal to or less than 100 nm for an arrangement pitch of 40 nm, equal to or greater than 200 nm and equal to or less than 400 nm for an arrangement pitch of 100 nm, and equal to or greater than 50 nm and equal to or less than 400 nm for an arrangement pitch of 200 nm.